Spark plug



3 6 7 4 4 1 Y T M m U H u N AMM DA DID & H G

Mar. 6, 1923.

S Dal/ azer? INVENTOR rromqzv Patented Mar. 6, i923.

' UNITED "STATES GEORGE SAMUEL DAUGHERTY, OF BLUE RIVER, WISCONSIN.

SPARK PLUG.

Application filed January 3, 1921. Serial No. 434,626.

To all whom it may concern Be it known that I, GEORGE 'S. DAUGH- ERTY, a citizen of the United States, residing at Blue River, in the county of Grant and State of Wisconsin, have inventednew and useful Improvements in Spark Plugs, of which the following is a specification.

This invention relates to spark plugs as used in connection with internal combustion engines and an object of the invention is to providea positive spark plug which is constructed to materially reduce filling of the plug by carbon and a plug which is practically self cleaning.

Other objects of the invention will appear in the following detailed description and in the accompanying drawings wherein:

Fig. 1 is a side elevation partly in section of the improved spark plug.

Fig. 2 is a horizontal section throu h the spark plug taken on the line 2-2 of ig. 1.

Fig. 3 is a fragmentary perspective of the central electrode of the spark plug.

Referring more particularly to the drawing the improved spark plug embodies the usual metal shell 1 provided with a threaded shank 2 adapted for threadable engage- I ment in a cylinder head of an internal combustion engine which shell receives therein 30 theusual porcelain or insulator 3 centrally of which the central electrode 4 of the plug extends. The central electrode 4 of the spark plug is constructed of electricity conducting material and carries the usual wire binding means 5 on its upper end while its lower end 6 is flattened, being substantially rectangular shape in cross section and providing an increased sparking surface 7 at its lower end which is spaced from and c0- acts with the disc electrode 8. The disc electrode 8 has a stem 9 formed thereon by means of which the disc-electrode is connected to the shell 1. The disc electrode 8 extends horizontally, and is positioned beneath and spaced from the lower sparking end 7 of the central electrode 4 forming the spark gap through which the electric current passes in spark form for igniting the 1 When the electric current passed into the spark plug is comparatively great a relatively large spark will pass between the electrodes 4 and 8 owing to the shape of the sparking end of the central electrode 4 and in case the current is relatively weak the spark will jump from any portion of the sparking end 7 tothe disc 8.

It is, of course, to be understood that the invention may be constructed in various other manners and the parts associated in different relations and, therefore, I do not desire to be limited in any manner except as set forth in the claim hereunto appended.

Having thus described my invention what I claim is:

In a spark plug, a central electrode having a rectangularly shaped sparking surface horizontally disposed, a disc electrode arranged horizontally in spaced parallel relation to the sparking surface of the central electrode, and a stem projecting from the disc electrode and secured to the plug.

' In testimony whereof I aflix my signature.

GEORGE SAMUEL DAUGHERTY. 

